This is a popular trail that leads to a great plunging waterfall in a gorge. The trail is mostly very easy, but has a few rocky sections and a few dry, dusty sections. Most of it is shaded, and you'll be able to see the stream nearly the whole time.
This trail begins from the Tamanawas Trailhead Parking, which is right off the west side of 35. There is room for 30+ cars and additional overflow parking north on the east side of 35, which may be needed on busy weekends.
From the parking lot, head past the information kiosk and turn to the north. Cross the nice bridge over East Hood River and follow East Fork Trail #650
north. You'll be able to see East Hood River below you. After about 0.5 miles, you'll turn left/west and come to a three way intersection - head west on Tamanawas Falls
Trail. The trail will descend to Cold Spring Creek and cross on a log bridge.
Thereafter, the trail will follow the north side of the creek and slowly ascend. There are views of the creek along this section. You'll come to an open rock slide area at the intersection with Tamanawas Tie Trail #650B. This section is rocky and can slide a bit, so be mindful. Also keep an eye out for the new-ish switchback. Shortly after this, the trail will level out, and you'll come to the falls.
Enjoy the beautiful falls, but be careful to not loosen rocks if you explore up the slope, as rocks can fall down. You'll need to retrace your steps to get back to the trailhead.